Purpose This core will provide chemical synthesis services and expertise in probe development for subprojects within the Program. The majority of the service component will be developed to synthesis, purification, and analysis of peptides and caged compounds. Technical assistance in the use of commercial caged compounds will be provided including chromatographic analysis of compound purity, and determination of extent of photo-conversion under specific experimental conditions. Many of the compounds being used in the subprojects are not commercially available and mus be prepared on a regular basis. In some instances, compounds need to be radiolabeled, or have biotin or fluorophores attached for addressing specific issues regarding a compounds stability, localization, or effective concentration in cells. Labeling and the flexibility to otherwise customize reagents for specific purposes represent two of many significant advantages of having 'in house' chemical synthesis capabilities. Core staff in consultation with subproject personnel will design and implement synthetic strategies based upon the requirements of the physiological or biochemical system under investigation.